Buggy code:
public class Repository { private File folder ; private List < Commit > commits ; private List < Tag > tags ; public Repository ( File folder ) throws InvalidRepositoryException { } public List < Commit > getCommits ( ) throws Exception { } public List < Commit > getCommits ( boolean update ) throws Exception { } public List < Diff > getUncommitedDiffs ( ) { } public List < Diff > getDiffs ( Commit c ) { } public List < Tag > getTags ( ) throws Exception { } public List < Tag > getTags ( boolean update ) throws Exception { } public void createTag ( Tag tag ) throws Exception { } public void createTag ( Tag . Type type , String name , Commit c , String message ) throws Exception { } public void deleteTag ( String name ) throws Exception { } public List < String > run ( String c ) throws Exception { } public List < String > run ( String ... c ) throws Exception { } public Process start ( String ... c ) throws Exception { } public byte [ ] readBinary ( String [ ] c ) throws Exception { } public boolean hasUnstagedFiles ( ) throws Exception { } public List < String > getStatus ( ) throws Exception { } public List < Change > parseStatus ( ) throws Exception { } public void stage ( String path ) throws Exception { } public void unstage ( String path ) throws Exception { } public void commit ( String message ) throws Exception { } public void commit ( String message , CommitOption mode ) throws Exception { } public List < Remote > getRemotes ( ) throws Exception { } public void addRemote ( String name , String path ) throws Exception { } public void removeRemote ( String name ) throws Exception { } public void editRemote ( String name , String path ) throws Exception { } public void init ( ) throws Exception { } public String getFileAt ( Commit c , String repopath ) throws Exception { } public String getAuthorName ( ) throws Exception { } public String getAuthorEmail ( ) throws Exception { } public String getAuthorString ( ) throws Exception { } public boolean isValidRepo ( ) { List < String > lines = null ; try { lines = run ( "git" , "rev-parse" , "--is-inside-work-tree" ) ; } catch ( Exception e ) { e . printStackTrace ( ) ; } <START_BUG> return ( lines != null ) && ( lines . get ( 0 ) . equalsIgnoreCase ( "true" ) ) ; <END_BUG> } public void revert ( Commit c ) throws Exception { } public void reset ( Commit c , ResetMode mode ) throws Exception { } public Branch getCurrentBranch ( ) throws Exception { } public List < Branch > getBranches ( ) throws Exception { } public Branch parseBranch ( String line ) { } public Commit getCommit ( String hash ) { } public void checkout ( Branch b ) throws Exception { } public void archive ( File output , Commit c ) throws Exception { } public void archive ( File output , String prefix , String format , Commit c ) throws Exception { } public String [ ] getArchiveFormats ( ) throws Exception { } public boolean isTracked ( File file ) throws Exception { } public List < File > getTrackedFiles ( ) throws Exception { } public void push ( boolean setupstream ) throws Exception { } public File getFolder ( ) { } public String getName ( ) { } public String getAbsolutePath ( String s ) { } public File getAbsoluteFile ( String s ) { } }

Fix:
return ( ( lines != null ) && ( ( lines . size ( ) ) > 0 ) ) && ( lines . get ( 0 ) . equalsIgnoreCase ( "true" ) ) ;